Polyurethane foam is a versatile material for many applications like acoustic, thermal insulation, as well as for energy absorption. The main aim of this paper is to improve acoustic properties by adding weight percentage of 2, 4, and 6 of magnesium hydroxide (Mg(OH)2) micro-particles in polyurethane (Pu) foam. To investigate the influence of micro-particles on acoustic properties, the samples are tested in an impedance tube to measure sound absorption coefficient. The experimental results are compared to finite element results predicted from Johnson–Champoux–Allard model. For thermal properties, the samples are experimented in thermal conductivity and fire retardant test. The results indicate that the significant improvement in the acoustic and thermal properties due to the addition of magnesium hydroxide. © 2021, Springer Nature Singapore Pte Ltd.